1. Field of the Invention
The present invention relates generally to safety guards for machine tools. More particularly, the invention concerns a safety guard to prevent an operator from coming into contact with the moving parts of automobile brake and rotor turning specialty lathes of the character used in the automotive trades to dress the surfaces of brake drums and rotors.
2. Discission of the Prior Art
A lathe is a widely used machine tool for revolving a piece of material so as to enable a cutting tool to shape it into a component of circular cross-section. Rotational movement is imparted to the work piece by a work spindle which is typically mounted in the headstock of the lathe. The spindle is rotated at a controlled rate of speed by motor means such as an electrically operated motor.
As a general rule, during operation of a conventional engine lathe to machine a work piece, the operator is exposed to the rotating work piece and to the rotating gripping devices which hold the work piece. This undesirable condition can expose the operator to the risk of substantial injury if the operator or parts of the operator's clothing inadvertently comes into contact with the rotating components.
While engine lathes are typically found in machine shops and are routinely operated by skilled, well-trained machinists, certain types of specialty lathes are found in a non-machine shop environment. Exemplary of such specialty lathes are those used in the automotive trades to dress the surfaces of automotive brake drums and rotors. These specially designed lathes are often located in garages, muffler shops, service stations and the like, and are sometimes operated by mechanics who are often less skilled and less well trained than journeyman machinists. These so called brake lathes, like conventional engine lathes, include a rotating spindle upon which the work piece is mounted so that it can be controllably rotated relative to one or more cutting tools. More particularly, the work pieces which are mounted on the spindle consist either of automobile brake drums or automobile brake rotors and the cutting tools of the machine functions to dress the surfaces of the drum or rotor which are engaged by the brake shoes or the brake pads. A well known manufacturer of disc/rotor and combination drum/disc brake lathes with which the apparatus of the present invention can be used, is Hennessy Industries, Inc. of La Vergne, Tenn.
The conventional automobile brake drum which typically cooperates with hydraulically actuated, internally expanding brake shoes, is generally of a configuration that can present a substantial hazard to the machine operator during the dressing operation wherein the drum is being rotated at relatively high speed. The automobile rotor, when rapidly rotated on the spindle of the specially designed turning lathe, can similarly present a hazard to the unprotected and sometimes relatively unskilled machine operator.
While some attempts have been made in the past to provide guards for brake lathes, none meet Federal Safety Standards set out in 29 C.F.R. 1910.212 or the California standards set out in Title 8 of the California Code of Regulations (CCR) Section 4002(a).
The thrust of the present invention is to provide a novel, easy-to-use safety guard which meets both the aforementioned Federal and California safety standards and can readily be interconnected with specialty lathes of the character used to dress the brake engaging surfaces of automobile brake drums and rotors. When in position on the machine, the safety guard of the invention safely encloses the rotating brake drum or rotor and protects the machine operator from accidentally contacting the work piece during the surface dressing operation.